Foam indicating apparatus for steam boilers



Oct. 23, 1934. R. w. SENIFF FOAM INDICA'IING APPARATUS FOR STEAM BOILERSFiled Feb. 23, 1932 r i H n n Nu 0% m &M 1 e @M Wm H; MM

Patented Oct. 23, 1934 FOAM INDICATING APPARATUS FOR STEAM BOILERSRussell Wade Seniif, Bloomington, Ill. Application February 23, 1932,Serial No. 594,571

5 Claims.

This invention relates to steam boilers and, more particularly, todevices for indicating the height or amount of foam therein.

The principal object of the invention is the provision of a new andimproved device for indicating the presence of foam above apredetermined level in steam boilers of locomotives and of other typesof steam engines.

A further object of the invention is the provision of new and improvedmeans for detecting the presence of an excessive amount of foam in steamboilers whereby excessive concentration of soluble salts in the waterwithin said boilers may be prevented with a minimum amount of labor andexpense.

A further object of the invention is the provision of a new and improvedfoam detecting device for steam boilers that is inexpensive tomanufacture, which may be easily and readily installed on theconventional steam boiler, that is composed of few parts and that isefiicient in operation.

Other and further objects and advantages of the invention will appearfrom the following description taken in connection with the accompanyingdrawing, in whichi Fig. 1 is a side elevation of a portion of alocomotive boiler with parts broken away and showing the invention inposition thereon, the boiler being shown more or less diagrammatically;

Fig. 2 is a side elevation of a portion of a boiler with parts brokenaway and showing the modified form of the invention in position thereon;and

Fig. 3 is a vertical section through the boiler and insulating plug ofthe modified form of construction shown in Fig. 2 and showing theindicator and the circuit diagrammatically with parts enlarged.

Under certain conditions water in steam boilers tends to foam and froth,and when this be-' comes excessive this foam and froth is carried overwith the steam as water into the cylinders,

thus impairing the lubrication of the engine which is likely to causemore or less damage to the mechanism. 7

While there are probably a number of causes contributing to foaming, oneof the principal causes is the concentration of dissolved salts in thewater of the boiler. It has been found by experiment that in the averagelocomotive boiler which operates around 200 lbs. pressure at 387 degreesFahrenheit, the water will foam when the concentration of the solublesalts inthe water amounts to about one part in 250. Sudden increases inload, that is, increase in use of steam,

more especially when the water in the boiler is at the foaming stage,will cause excessive foaming due to the temporary release of pressure onthe water and to the consequent excessive generation of steam throughoutthe mass which violently agitates the same.

In order to prevent foaming, it is common practice for the engineer, oroperator, to blow off the boiler at frequent intervals and to introducefresh water in' order to lower the ratio of the soluble salts in thewater.

Such practice results in loss of excessive amounts of hot water andconsequent loss of fuel due to the fact that the engineer, or operator,having no means of determining the amount of water tobe discharged,andin order to be safeinvariably blows off the boiler in excess of theamount necessary. The present invention seeks to remedy thesedifficulties by the provision of means for determining when there is anexcessive accumulation of foam in the boiler.

It has been determined by actual tests thatthere is under normaloperating conditions an average fuel waste of 2.7% due to the heat lostin the excessive water discharged from the boiler to prevent foaming.This waste of heat units may be saved by the use of some means forindicating to the engineer the foam condition of the boiler so that onlythe amount of water concentrate necessary to prevent excessive foamingneed be discharged.

The engineer, by observing the indicator, may, with a little experience,learn to prevent excessive foaming in the boiler with a minimum amountof heat loss.

Referring now to the drawing, the reference character 10 designates alocomotive boiler'having the usual fire box 11, crown sheet 12, flues 13and steam dome 14, as are usual in such constructions. 'The boiler isalso provided in one of its water legs with the usual blow-off valve 15which is operated by the lever 16 within the cab 17 in the usual manner.7

The parts thus far described are shown more or less diagrammatically andmay be of the usual or any well-knownconstruction. Since the details ofthese parts constitute no part of the present invention, it is notthoughtnecessary to describe or illustrate the same. 1

Suitablemeans are provided for indicating to the engineer when the foamin the space 18 above the water level reaches a predetermined height. 1

'It has been. found by extensive experiments that foam willconductelectricity and this pr0perty of the foam is utilized to indicate itsheight in the boiler.

In the form of construction selected to illustrate one embodiment of theinvention, which is by way of example only, an electrode 19 is securedin the shell 21 of the boiler above the normal water line. It isinsulated from the boiler. similar to a spark plug. This electrode isconnec'tedwith a suitable source of electric energy as the generator 22and with an indicator 23.

The indicator may be in the form of an electriclamp 24 within a casing25 which is provided with a bulls eye 26 opposite the lamp 24 of anydistinctive color, as may be desired. The electrode 19, generator 22 andindicator 23 are shown as being in series and grounded as at 2'? on theboiler.

The lower end of the electrode is located a predetermined distance abovethe normal water line of the boiler and when sufficient foam accumulateswithin the boiler to come incontact with the electrode to close thecircuit, the signal will be energized to indicate to the engineer thepresence of foam within the boiler. I

If desired, a plurality of electrodes may be employed for indicatingdifferent heights. In the form of construction shown in Fig. 1, twoelectrodes 19 and 28 are employed. 7

The electrode 28 terminates at a higher level than the electrode 19 andis in a separate circuit withthe source of current and with a secondlamp 31. The lamp 31 has a bulls eye 32 in front of it. The electrode23may be arranged to terminateat the uppermostlevel that is safe to permitfoam to accumulate in the space 18.

, If more than one electrode be employed, they are preferably ofdifferent colors. Only two signals are shown and the first signal may beamber and the other red so that the engineer will know that when theamber signal is flashed, the foam is collecting within the boiler buthas not reached the danger point. When the red signal is flashed, hewill know the danger point is nearor hasbeen reached, depending upon thearrangement of the electrodes and signals.

In the operation of the device, when the foam rises in the space 18above the water into contact with the lower end of electrode 19 the foamwill complete the circuit through the electrode 19, the generator 22 andthe lamp 24, thereby energizing the amber signal and when it rises stillfurther and contacts with the electrode 28 the circuit will be completethrough the. generator 22 and the lamp '31, thereby flashing the-redsignal, and warning the engineer of the presence of an excessive amountof foam in the boiler.

While in the invention described above colored visible signalsareemployed, it is. understood that other forms of signals may be used,either visible or audible. a I I For instance, in the form ofconstruction shown, in Figs. 2 and 3 an indicator similar to an ammetermay be employed. In this form of construction, a double electrode 33 isemployed. As shown, the? central electrode 34 is insulated from theplug35 with any suitable insulatingmaterial 36, such as bakelite orporcelain. The other electrode 37 may be in the form of wire woundspirally on'a support 40 which may be of bakelite or other insulat ingmaterial. If desired both terminals, or either, may be of wire supportedin any suitable manner. If desired, either or both may bemade ofmaterial. having a high electrical resistance, sothat as the foam riseson the same, the resistance to the flow of current will materiallyincrease. The plug shell 35 carrying the electrode 37 is mounted on theboiler shell 21 and the electrode 34 is electrically connected to asource of energy as the battery 33 and to an indicator 39 which,in'turn, is grounded on the boiler as'at 41.

In the operation of thedevice, when the foam rises into contact with thelower ends of the electrodes 34 and 37, the circuit will be completedbetween the battery, the indicator'and theelectrodes. This will actuatetheindicatori 39 for indicating to the engineer the presence of foamwithin the space occupied by the electrodes. As the height of the foamincreases, the resistance of electrodes will correspondingly decrease Jwith a consequent increase in the strength of the current which will beindicated by the hand 42 of theindicator 39.

'Since the strength of the current will vary inversely as theresistance, and since the resistance will decrease as the foam risesalong the electrodes, the indicator 39 which measures the current willindicate the height of the foam in the boiler.

, Instead of arranging the electrodes parallel they may be so arrangedthat they diverge downwardly whereby asythe height of the foam rises thespace betweenthem for the current to traverse will become less and hencethe strength of the current will increase, The indicator will respond tothis increase and therebyindicate the height of the foam in said space.

. What I claim, therefore, is:

1. A device for indicating the foam level in steam boilers, comprisingan insulated electrode extending into said boiler and terminating abovethe normal water level therein and an electrical circuit connected tosaid electrode and adapted to be closed when foam in said boiler risessuificiently to contactsaid electrode.

2. A device for indicating the foam level in steam boilers, comprisingan insulated electrode extending into said boiler and terminating abovethe normal water level therein, an electrical cir-- cuit connected tosaid electrode and adapted tobe closed when foam in said boiler risessufficiently to contact said electrode and visible signal means in saidcircuit actuated by the closing thereof.

3. In combinationwith a steam boiler having the conventional boilershell and crown sheet spaced from the upper portion of said shell toform a steam ,space above the normal water line in said boiler, anindicator and means extending into said .space and terminating above thenormal waterline in saidboiler and-normally out of contact with foam insaid boiler for operating said indicator'onlywhen foam in said spacerises intowhen it rises into contact with another of said electrodesanother of said lamps will be energized for indicating the height offoam within: said boiler.

.5. An apparatus for indicating the height of foam within a'steam boilercomprising a plurality of insulated electrodes of materially differentlengths adapted to be secured in a boiler shell and occupying positionswholly above the water leveltherein, a source of electric energy and anindicator'device comprising a lamp for each electrode,'each electrodebeing in electrical connection with said source of electric energy and acorresponding lamp.

. RUSSELL WADE SENIFF.

